Surface structure of fiber-reinforced composite implant and its effect on the attachment of implant to simulating bone material

Abstract

Objective: Fiber-reinforced composite (FRC) made of polymethyl methacrylate (PMMA) and E-glass fibers has been developed for bone segment defect reconstructions. It has been shown that exposed glass fibers predispose intergration of implant to bone. The aim of this study was to investigate how fibers of the implant surface can be exposed by solvent treatment and how the exposed fibers with different orientations effect the attachment of the implant to a bone simulating material

Materials and methods: Test specimens were made of PMMA with continuous E-glass fibers that were continuosly oriented either along the long axis of the specimen, perpendicularly to the long axis, or randomly as short fibers. PMMA specimens without fibers served as control material for the solvent treatment by tetrahydrofuran (THF). Solvent treatment time to dissolve PMMA around the fibers varied from 5 to 30 minutes. The advanement of the dissolutin was measured microscopically at appointed time intervals after drying of the specimens. After exposing the fibers, the specimens were embedded in the plaster of Paris, which simulated mechanical locking to bone. Pull-out tests of specimens from the plaster of Paris were undertaken to determine magnitude of attachment.

Results: all the specimens dissolved as function of time, but the specimens with fibers along the direction of long axis of specimen began to dissolve significantly faster than specimens in other groups. however, the test specimens with randomly oriented short fibers, showed the highest depth of dissolution after 30 minutes.
The pull-out test showed that the PMMA specimens with fibers were retained better with the plaster of Paris than specimens without fibers. However, direction of the fibers considerably influenced the attachmnet force.

Conclusions: The orientation of the glass fibers had effect on the dissolving depth of the polymer matrix of the composite. Exposed glass fibers, which protruded out form the surface of the specimens, attached effectively the specimen to the modeling materials of bone.

Reference
Surface structure of fiber-reinforced composite implant and its effect on the attachment of implant to simulating bone material
Hautamäki MP, Puska M, Kopperud HM, Aho AJ, Vallittu PK
In: Repair of segmental bone defects with fiber-reinforced composite: a study of material development and an animal model of rabbits by Mikko Hautomäki, University of Turku, 2012